What is the most common cause of facial nerve paralysis?

Most Common Cause of Facial Nerve Paralysis

Bell's palsy (option C) is the most common cause of facial nerve paralysis. 1, 2

Evidence Supporting Bell's Palsy as the Most Common Cause

The American Academy of Otolaryngology-Head and Neck Surgery clearly states in their clinical practice guideline that "Bell's palsy is the most common acute mono-neuropathy, or disorder affecting a single nerve, and is the most common diagnosis associated with facial nerve weakness/paralysis." 1

This is further supported by multiple research studies:

• Bell's palsy is described as "the most common mononeuropathy that causes acute unilateral facial paralysis or paresis" 2
• It is consistently referred to as "the most common cause of unilateral facial paralysis" 3, 4

Differential Diagnosis of Facial Paralysis

While Bell's palsy is the most common cause, it's important to recognize other potential etiologies:

1. Traumatic causes (including options A and B):

   • Parotid surgery can cause iatrogenic facial nerve injury
   • Faciomaxillary injuries may result in facial nerve damage
   • Temporal bone fractures can cause facial paralysis, which may present with delayed onset 5

2. Neoplastic causes (including option D):

   • Parotid carcinoma
   • Other tumors affecting the facial nerve pathway

3. Other causes:

   • Infections (viral, bacterial)
   • Congenital conditions
   • Toxic exposures 5

Clinical Presentation and Diagnosis

Bell's palsy typically presents with:

• Rapid onset of unilateral facial weakness or complete paralysis
• Symptoms peak within 72 hours
• May be accompanied by post-auricular pain, drooping eyelid, taste disturbances, and decreased tear production 2

Warning signs that suggest an alternative diagnosis to Bell's palsy include:

• Gradual, progressive onset (rather than acute)
• Associated neurological symptoms
• Bilateral involvement
• Lack of improvement over time 4, 6

Management Considerations

For confirmed Bell's palsy, treatment includes:

• Oral corticosteroids are strongly recommended for adult patients 7
• Antiviral therapy may be considered as an optional treatment 7
• Eye protection is crucial for patients with impaired eye closure 7

Common Pitfalls

1. Misdiagnosis: Not all facial paralysis is Bell's palsy. A thorough evaluation is necessary to rule out other causes, particularly when presentation is atypical 3, 4

2. Delayed treatment: Early intervention with corticosteroids improves outcomes for Bell's palsy 7, 6

3. Inadequate follow-up: Lack of recovery after 4 months should prompt further diagnostic workup 6

4. Neglecting eye protection: Patients with impaired eye closure need protective measures to prevent corneal damage 7

In summary, while facial nerve paralysis can result from various causes including surgical procedures, trauma, and tumors, Bell's palsy remains the most common etiology.